patch for improved mousedragging. We were able to test this on my eeepc

and get a very obvious speedup in performance. This adds a configurable
'interval' to the dragpan control (and an interval to the 'drag' control,
defaulting to 0px). Patch put together by tcoulter. (Closes #1509) 


git-svn-id: http://svn.openlayers.org/trunk/openlayers@7608 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Control/Navigation.js

@@ -30,6 +30,12 @@ OpenLayers.Control.Navigation = OpenLayers.Class(OpenLayers.Control, {
      */
     dragPan: null,
 
+    /**
+     * APIProprety: dragPanOptions
+     * Options passed to the DragPan control.
+     */
+    dragPanOptions: null,
+
     /** 
      * Property: zoomBox
      * {<OpenLayers.Control.ZoomBox>}
@@ -41,7 +47,7 @@ OpenLayers.Control.Navigation = OpenLayers.Class(OpenLayers.Control, {
      * {Boolean} Whether the mousewheel should zoom the map
      */
     zoomWheelEnabled: true, 
-
+    
     /**
      * Constructor: OpenLayers.Control.Navigation
      * Create a new navigation control
@@ -110,7 +116,9 @@ OpenLayers.Control.Navigation = OpenLayers.Class(OpenLayers.Control, {
                                           'double': true, 
                                           'stopDouble': true
                                         });
-        this.dragPan = new OpenLayers.Control.DragPan({map: this.map});
+        this.dragPan = new OpenLayers.Control.DragPan(
+            OpenLayers.Util.extend({map: this.map}, this.dragPanOptions)
+        );
         this.zoomBox = new OpenLayers.Control.ZoomBox(
                     {map: this.map, keyMask: OpenLayers.Handler.MOD_SHIFT});
         this.dragPan.draw();